There would be no dogs without breeding. The reason we have dogs to begin with is because we took the wolf and over thousands of years bred it for desirable traits. Dogs didn't just exist. We took nature and bent it to our will. Dogs remain to this day the only large predator we've ever managed to domesticate.
Breeders, at least the good ones who only have a handful of litters a year and make buyers sign spay and neuter contracts, are not the problem. The problem is irresponsible owners who don't get their dogs fixed, and then dump a litter of puppies at a shelter. The problem is puppy mills that breed hundreds of litters a year with no regard for their health or well-being. The problem is people who get a dog and then find they can't handle it, so they dump it off on a pound or shelter.
Both of my current dogs required a contract to be signed. That contract dictated that I had to spay/neuter the dog by a certain point in its life. For the Shepherd it was by a year of age (the breeder recommended I wait at least eight months for proper development). I don't recall what it was for the Boxer, but she got done around the same age. The contracts also stated that, in the event that I find myself unable or unwilling to continue caring for the dog, I am to return it to them so that they can either keep it or place it in a new home. That, to me, is pretty responsible breeding.
It's not about certain breeds being superior or inferior. Different breeds absolutely have very different personalities. My German Shepherd acts nothing like my Boxer, even though I raised them the same. One is cuddly and affectionate. The other wants a job to do and likes a little personal space. When I buy a Boxer, I know exactly what I am getting. I value that, because I already know I like Boxers and that they fit how I like to live my life, very active at times but content to chill on the couch all afternoon on a 100 degree summer day.
There are certainly health issues with pure bred dogs, and likely always will be. But if you buy from reputable breeders, you nullify those risks to the greatest extent possible. My first Boxer lived to ten and a half, which is just over the average life span of the breed (which is 8 to 10 years). My Shepherd is going on 9 without ever having to go to the vet for anything other than his yearly checkup and vaccinations his entire life so far. The current Boxer isn't quite 3 yet and has thus far been healthy other than allergies, which are fairly common for the breed.
At any rate, the appeal of a pure bred dog to me is, as I mentioned, knowing what you're going to get. There are plenty of mutts that may act like Boxers, but I know a Boxer is going to act like a Boxer.